This invention relates generally to filter presses of the continuous type such as are employed for extracting water or other liquids from various fluid or semi-fluid feed materials. The invention is particularly applicable to extracting water from various pulps, slurries, or other semi-solid materials, including, for example, paper pulps, sewage sludges, vegetable and fruit pulps, tomato and grape pomace, citrus peel, fish or fish processing slurries, cannery wastes and brewers and distillers grains.
U.S. Pat. No. 3,447,450, dated June 3, 1969, discloses a continuous filter press of the type making use of wheels provided with conical shaped screens on their inner faces and carried by side structures in such a manner that the intersecting axes of the wheels during operation are out of alignment. When the wheels are rotated, portions of the screens are brought into proximity in a pinch zone, and other portions of the screens are separated to form a feed receiving space. Feed material (e.g., a slurry) introduced into the feed receiving space is carried through the pinch zone to express liquid from the same, and the material leaving the pinch zone is diverted through a discharge opening in the surrounding casing. A plow serves to divert the material through the discharge opening, and as shown in U.S. Pat. No. 3,447,450, the outer end of the plow is secured to the casing and the inner wedge-shaped end is disposed between the central portions of the wheels. Thus the plow is supported cantilever fashion by the attachment of its outer end to the casing. The journalling of the wheels as disclosed in U.S. Pat. No. 3,447,450 makes use of stud shafts secured to the wheels and journalled on the adjacent side structures. Also thrust bearing means is interposed between the inner faces of the side structures and the adjacent faces of the wheels in regions near the outer peripheral margins of the wheels. The lateral dimensions of the inner end of the plow must be relatively close together in the pinch zone. With the construction shown in said patent, it is difficult to design and construct a plow having sufficient strength to withstand the forces to which it is subjected, particularly when the press is constructed in the larger sizes or when it is desired to have the screens very close together in the pinch zone to facilitate the handling of slippery feed materials. Also the journalling of the wheels by use of simple stud shafts has some disadvantages which again are more apparent for machines made in the larger sizes. Stud shafts do not permit access to the space between the wheels through the side structures and the wheels, and therefore all clean-up operations must be carried out by swinging the side structures apart to open the space between the wheels.